scholarly journals Kalman Algorithm Based Electrical Impedance Tomography Imaging

2019 ◽  
Vol 4 (4) ◽  
pp. 52-55
Author(s):  
Md Rabiul Islam
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Signal To Noise Ratio ◽  
Spatial Location ◽  
Element Model ◽  
Target Object ◽  
Dielectric Constants ◽  
The Body ◽  
Impedance Tomography ◽  
Ac Current

Electrical Impedance Tomography (EIT) is a non-invasive imaging technique that displays changes in conductivity within a body. This method finds application in biomedical and geology. EIT finds use in medical applications, as the different tissues of the body have different conductivity and dielectric constants. In this paper a phantom model is designed considering Finite Element Model (FEM). AC current of amplitude 1 mA and frequency 1 KHz is applied considering adjacent protocol with noise less and noisy cases. From the computed voltage data image is reconstructed using Kalman algorithm. For noisy case noise levels equal to Signal-to-Noise Ratio (SNR) 30 dB, 15 dB and 7 dB were considered. Kalman algorithm is studied for EIT image reconstruction in noise free and noisy case, in terms of shape, size, spatial location of the target object.

Electrical Impedance Tomography of Cell Viability in Tissue With Application to Cryosurgery

2004 ◽  
Vol 126 (2) ◽  
pp. 305-309 ◽  
Author(s):  
Rafael Davalos ◽  
Boris Rubinsky
Keyword(s):  
Electrical Properties ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Cell Damage ◽  
Membrane Integrity ◽  
The Body ◽  
Impedance Tomography ◽  
Cell Membrane Integrity ◽  
Minimally Invasive Surgical Procedure ◽  
Minimally Invasive Surgical

Tissue damage that is associated with the loss of cell membrane integrity should alter the bulk electrical properties of the tissue. This study shows that electrical impedance tomography (EIT) should be able to detect and image necrotic tissue inside the body due to the permeabilization of the membrane to ions. Cryosurgery, a minimally invasive surgical procedure that uses freezing to destroy undesirable tissue, was used to investigate the hypothesis. Experimental results with liver tissue demonstrate that cell damage during freezing results in substantial changes in tissue electrical properties. Two-dimensional EIT simulations of liver cryosurgery, which employ the experimental data, demonstrate the feasibility of this application.

scholarly journals On the Implementation of Simultaneous Multi-Frequency Excitations and Measurements for Electrical Impedance Tomography

Sensors ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 3679 ◽  
Author(s):  
Mathieu Darnajou ◽  
Antoine Dupré ◽  
Chunhui Dang ◽  
Guillaume Ricciardi ◽  
Salah Bourennane ◽  
...  
Keyword(s):  
Electrical Impedance Tomography ◽  
High Speed ◽  
Electrical Impedance ◽  
Fourier Transforms ◽  
Imaging Technique ◽  
Signal To Noise Ratio ◽  
Data Acquisition System ◽  
Impedance Tomography ◽  
Field Programmable ◽  
Propagation Of Uncertainties

The investigation of quickly-evolving flow patterns in high-pressure and high-temperature flow rigs requires the use of a high-speed and non-intrusive imaging technique. Electrical Impedance Tomography (EIT) allows reconstructing the admittivity distribution characterizing a flow from the knowledge of currents and voltages on its periphery. The need for images at high frame rates leads to the strategy of simultaneous multi-frequency voltage excitations and simultaneous current measurements, which are discriminated using fast Fourier transforms. The present study introduces the theory for a 16-electrode simultaneous EIT system, which is then built based on a field programmable gate array data acquisition system. An analysis of the propagation of uncertainties through the measurement process is investigated, and experimental results with fifteen simultaneous signals are presented. It is shown that the signals are successfully retrieved experimentally at a rate of 1953 frames per second. The associated signal-to-noise ratio varies from 59.6–69.1 dB, depending on the generated frequency. These preliminary results confirm the relevance and the feasibility of simultaneous multi-frequency excitations and measurements in EIT as a means to significantly increase the imaging rate.

scholarly journals Evaluation of reconstruction parameters of electrical impedance tomography on aorta detection during saline bolus injection

2016 ◽  
Vol 2 (1) ◽  
pp. 511-514 ◽  
Author(s):  
Florian Thürk ◽  
Andreas D. Waldmann ◽  
Karin H. Wodack ◽  
Constantin J. Trepte ◽  
Daniel Reuter ◽  
...  
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Bolus Injection ◽  
Noise Figure ◽  
Early Stage ◽  
The Body ◽  
Detection Accuracy ◽  
Impedance Tomography ◽  
Saline Bolus ◽  
Hemodynamic Processes

AbstractAn accurate detection of anatomical structures in electrical impedance tomography (EIT) is still at an early stage. Aorta detection in EIT is of special interest, since it would favor non-invasive assessment of hemodynamic processes in the body. Here, diverse EIT reconstruction parameters of the GREIT algorithm were systematically evaluated to detect the aorta after saline bolus injection in apnea. True aorta position and size were taken from computed tomography (CT). A comparison with CT showed that the smallest error for aorta displacement was attained for noise figure nf = 0.7, weighting radius rw = 0.15, and target size ts = 0.01. The spatial extension of the aorta was most precise for nf = 0.7, rw = 0.25, and ts = 0.07. Detection accuracy (F1-score) was highest with nf = 0.6, rw = 0.15, and ts = 0.04. This work provides algorithm-related evidence for potentially accurate aorta detection in EIT after injection of a saline bolus.

scholarly journals The Factorization Method for Electrical Impedance Tomography Data from a New Planar Device

2007 ◽  
Vol 2007 ◽  
pp. 1-7 ◽  
Author(s):  
Mustapha Azzouz ◽  
Martin Hanke ◽  
Chantal Oesterlein ◽  
Karl Schilcher
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Imaging Techniques ◽  
Factorization Method ◽  
The Body ◽  
Impedance Tomography ◽  
Type Method ◽  
Reconstruction Methods ◽  
Tomography Data ◽  
Electrical Impedance Tomography Data

We present numerical results for two reconstruction methods for a new planar electrical impedance tomography device. This prototype allows noninvasive medical imaging techniques if only one side of a patient is accessible for electric measurements. The two reconstruction methods have different properties: one is a linearization-type method that allows quantitative reconstructions; the other one, that is, the factorization method, is a qualitative one, and is designed to detect anomalies within the body.

scholarly journals Automated filtering in the nonlinear Fourier domain of systematic artifacts in 2D electrical impedance tomography

2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Melody Alsaker ◽  
Benjamin Bladow ◽  
Scott E. Campbell ◽  
Emma M. Kar
Keyword(s):  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Electrical Current ◽  
The Body ◽  
Fourier Domain ◽  
Reconstruction Method ◽  
Impedance Tomography ◽  
Conductivity Distribution ◽  
Frequency Regime ◽  
Internal Conductivity

<p style='text-indent:20px;'>For patients undergoing mechanical ventilation due to respiratory failure, 2D electrical impedance tomography (EIT) is emerging as a means to provide functional monitoring of pulmonary processes. In EIT, electrical current is applied to the body, and the internal conductivity distribution is reconstructed based on subsequent voltage measurements. However, EIT images are known to often suffer from large systematic artifacts arising from various limitations and exacerbated by the ill-posedness of the inverse problem. The direct D-bar reconstruction method admits a nonlinear Fourier analysis of the EIT problem, providing the ability to process and filter reconstructions in the nonphysical frequency regime. In this work, a technique is introduced for automated Fourier-domain filtering of known systematic artifacts in 2D D-bar reconstructions. The new method is validated using three numerically simulated static thoracic datasets with induced artifacts, plus two experimental dynamic human ventilation datasets containing systematic artifacts. Application of the method is shown to significantly reduce the appearance of artifacts and improve the shape of the lung regions in all datasets.</p>

scholarly journals Evaluation of Thoracic Equivalent Multiport Circuits Using an Electrical Impedance Tomography Hardware Simulation Interface

Technologies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 58
Author(s):  
Christos Dimas ◽  
Vassilis Alimisis ◽  
Ioannis Georgakopoulos ◽  
Nikolaos Voudoukis ◽  
Nikolaos Uzunoglu ◽  
...  
Keyword(s):  
Finite Element ◽  
Electrical Impedance Tomography ◽  
Electrical Impedance ◽  
Imaging Modality ◽  
Low Cost ◽  
Element Model ◽  
High Temporal Resolution ◽  
Thoracic Impedance ◽  
Impedance Tomography ◽  
Signal Sampling

Electrical impedance tomography is a low-cost, safe, and high temporal resolution medical imaging modality which finds extensive application in real-time thoracic impedance imaging. Thoracic impedance changes can reveal important information about the physiological condition of patients’ lungs. In this way, electrical impedance tomography can be a valuable tool for monitoring patients. However, this technique is very sensitive to measurement noise or possible minor signal errors, coming from either the hardware, the electrodes, or even particular biological signals. Thus, the design of a good performance electrical impedance tomography hardware setup which properly interacts with the tissue examined is both an essential and a challenging concept. In this paper, we adopt an extensive simulation approach, which combines the system’s analogue and digital hardware, along with equivalent circuits of 3D finite element models that represent thoracic cavities. Each thoracic finite element model is created in MATLAB based on existing CT images, while the tissues’ conductivity and permittivity values for a selected frequency are acquired from a database using Python. The model is transferred to a multiport RLC network, embedded in the system’s hardware which is simulated at LT SPICE. The voltage output data are transferred to MATLAB where the electrical impedance tomography signal sampling and digital processing is also simulated. Finally, image reconstructions are performed in MATLAB, using the EIDORS library tool and considering the signal noise levels and different electrode and signal sampling configurations (ADC bits, sampling frequency, number of taps).

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